Summary

Hydroxychloroquine sulfate is frequently used to treat patients with dermatomyositis. It has been associated with an increased risk of adverse skin reactions in these patients. This study was performed to find out whether subsets of adult dermatomyositis patients, characterized by antibodies, are at increased risk for these skin eruptions.

Why was the study done?

Hydroxychloroquine sulfate is frequently used to treat patients with dermatomyositis. It has been associated with an increased risk of adverse skin reactions in these patients. It is known that different groups of patients with dermatomyositis make autoantibodies that bind to different self-proteins and that these antibodies are associated with different clinical findings. For example, dermatomyositis patients with antibodies to the protein MDA5 are more likely to have lung disease and skin ulcers than those who do not have this antibody. This study was performed in a collaboration between Dr. Livia Casciola-Rosen at Johns Hopkins and Dr. David Fiorentino’s group at Stanford University to find out whether subsets of dermatomyositis patients with different autoantibodies are at increased risk for skin eruptions after taking hydroxychloroquine.

How was the study done?

This study was performed on banked serum samples (ie, a retrospective study) from an outpatient dermatology clinic at Standford University. All adult dermatomyositis patients who were treated with hydroxychloroquine between July 1, 1990 and September 13, 2016 were eligible for inclusion. If a skin eruption developed within 4 weeks of starting treatment, and resolved when treatment stopped, a patient was considered to have a treatment-associated skin reaction. Eight different antibody types that are found in myositis patients were tested for in the serum samples at Johns Hopkins University.

What were the major findings?

Of 111 patients included in the study, 23 (20.7%) developed a skin eruption that was determined to be the result of hydroxychloroquine treatment. Antibodies against the protein SAE1/2 were significantly associated with a hydroxychloroquine-associated skin eruption in these patients. In contrast, antibodies against MDA5 were significantly negatively associated with this. The types of skin eruptions were variable and included dermatomyositis flares, skin eruptions after sun exposure, as well as those that were red and itchy.

What is the impact of this work?

Adverse skin reactions to hydroxychloroquine treatment are relatively common in US patients with dermatomyositis. These new findings show that specific patient groups are at increased risk (patients with SAE1/2 antibodies) and decreased risk (patients with MDA5 antibodies) of developing these adverse skin reactions, which may help with treatment management.

About Erika Darrah

Erika Darrah, Ph.D. is an Assistant Professor of Medicine in the Johns Hopkins University Division of Rheumatology with an interest understanding the mechanisms that drive the development of rheumatic diseases.

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